There are a number of insole foot force sensing devices currently used for measuring force on the foot. For example, U.S. Pat. No. 4,745,930 to Confer, which is incorporated herein by reference, describes a flexible force sensing insole which incorporates multiple electrical switches which close after a certain threshold level of force is imposed on the insole. U.S. Pat. No. 5,033,291 to Podoloff et al., which is incorporated herein by reference, describes a force sensing device which uses a plurality of intersecting electrodes. The electrodes act as open circuit switches at each intersection which close when force is applied to the insole at that intersection location. The resistance between the two electrodes varies with the amount of force applied. U.S. Pat. No. 4,426,884 to Polchaninoff, which is incorporated herein by reference, describes a flexible force sensor which acts as an open circuit, closing with the application of force on the sensor and having resistance that varies with the amount of force.
Foot force measurement devices typically convert mechanical force into a suitable signal medium, usually electrical signals. The devices thus can be conveniently categorized according to the type of sensor used to convert changes in mechanical force to changes in electrical signals. These types of sensors include switches, strain gauge sensors that respond to mechanical deformation, single direct electronic force sensors, multiple direct electronic force sensors with random spacing, and multiple direct electronic force sensors with regular spacing.
U.S. Pat. No. 4,813,436 to Au, which is incorporated herein by reference, describes a motion analysis system that incorporates markers which are secured at various joints of a subject's body, and pressure-sensitive shoes or insoles which are worn by the subject. The subject is caused to perform motion such as walking or running. While performing this motion, the subject is televised by means of two video cameras. A display is provided which indicates the pressure applied to the subject's foot while performing the motion, as measured by the pressure-sensitive insoles. The remaining data supplied by the video cameras is processed to present various displays showing the gait, the angular position of the various joints of the subject, and various other information indicative of the particular walking characteristics of the subject. The data produced and processed by the system enables a practitioner to compare the subject's walking gait to that of a normal user.
U.S. Pat. Nos. 4,734,034 and 4,856,993 to Maness et al., which are incorporated herein by reference, describe a contact sensor for detecting points on a grid where the sensor is being contacted on opposing sides by teeth surfaces or other contacting points. The contact sensor includes two sets of parallel electrodes which are each formed of a thin, flexible supporting sheet. The electrodes are coated with a thin, resistive coating. Two such electrode structures are oriented at approximately right angles to create a grid where the intersecting electrodes cross separated by the resistive coatings. The resistive coatings may be made from conventional resistive inks and are optionally separated by a separation material, such as talcum or mesh. In the absence of an external force, the material between the electrodes sets provides a high resistance between intersecting electrodes. The composition of the intermediate layer results in a structure which provides a “switching” effect such that the resistance between electrodes is very high where there is no external pressure and changes to a comparatively low value at locations where external pressure is applied by two contacting points or surfaces.
U.S. Pat. No. 3,881,496 to Vredenbregt et al., which is incorporated herein by reference, describes techniques for electrically stimulating leg muscles using an air-filled chamber located in the sole of the shoe beneath the ball of the foot. The chamber is coupled through an air channel or a thin hose and a diaphragm to a microswitch located in the heel. The switch activates an electric pulse generator in synchronism with the normal walking pattern.
U.S. Pat. No. 3,974,491 to Sipe, which is incorporated herein by reference, describes a sensor having a fluid-filled chamber that is a continuous, resilient tube having a circular cross section. The tube is coiled under the heel and the sole of a patient's foot inside a sponge rubber footpad. The footpad is placed between adhesive sheets of flexible, dimensionally stable material such as rubber-coated fabric.
U.S. Pat. No. 3,791,375 to Pfeiffer, which is incorporated herein by reference, describes a remote displacement measuring device that is connected to two units, a heel unit and a toe unit, located in the insole. The units deflect and change their volume in accordance with the amount of load placed thereon. The displacement measuring device is signaled with an electrical alarm to indicate when a predetermined load on the units is reached. The displacement measuring device consists of a single sensor such as, for example, a bellows that measures the combined total displacement from both the heel and the toe unit.
U.S. Pat. No. 6,273,863 to Avni et al., which is assigned to the assignee of the present application and is incorporated herein by reference, describes a portable, self-learning adaptive weight bearing monitoring system for personal use during rehabilitation of orthopedic patients with fractures of the lower extremities. The system includes a flexible insole which is worn inside the shoe. The insole includes pressure and/or force sensor that measure the Ground Reaction Force (GRF) applied at key bearing points under the foot or other portions of the patient's lower extremity. The sensors are, in turn, connected through an A/D converter to a CPU that is connected so as to drive a stimulator that delivers closed-loop sensory stimulation (electrical, mechanical, and/or audio) as feedback to encourage the patient to load the optimal target weight for the limb for which the weight bearing force is being measured. Accurate real-time monitoring of the weight bearing during physical rehabilitation is also provided, and, through the use of closed-loop sensory stimulation, the patient is given continuous feedback for improving rehabilitation.
PCT Publication WO 04/008095 to Avni et al., which is assigned to the assignee of the present application and is incorporated herein by reference, describes a force sensor system for use in monitoring weight bearing on a location. The force sensor system comprises at least one a foot force sensor, a palm force sensor, and a knee force sensor. The foot force sensor comprises a flexible insole containing a plurality of inflatable pockets that are inflated with air or liquid. The palm force sensor and knee force sensor each comprise a wrap to be worn around the palm and knee, respectively. Each wrap comprises a pocket. Each pocket is connected to a tube that, in turn, connects with a pressure sensor and a connector coupling that is remote from the pocket. Each coupling contains a valve. The valve opens to allow inflation and deflation of each inflatable pocket. The pressure sensors measure the air or liquid pressure within each of the inflatable pockets, and convert the corresponding pressure signal into a suitable output signal medium, usually electrical signals. The output signal from the sensors provides accurate real time input data to a weight bearing biofeedback system or to control a stimulator for activation of an electronic orthosis to normalize dynamic gait patterns.
PCT Publication WO 01/36051 to Avni, which is assigned to the assignee of the present application and is incorporated herein by reference, describes a portable, self-learning adaptive weight bearing monitoring system for personal use during rehabilitation of neurological disorders and orthopedic lower limb injuries. The system includes a flexible insole or pad which includes at least one pressure and/or force sensor that measures the weight force applied to at least two monitored locations of at least one of the patient's limbs. The sensors are, in turn, connected through an A/D converter to a CPU that compares the distribution of weight on each monitored location of at least one limb to a target weight distribution. The target weight distribution is preferably based on subjective and objective parameters unique to the patient and the injury of the patient. The CPU is connected so as to drive a stimulator that delivers closed-loop sensory stimulation (visual, mechanical vibration, and/or audio) as feedback to encourage the patient to distribute weight more evenly on all monitored locations of at least one limb. Accurate real-time monitoring of the weight bearing during physical rehabilitation is also provided, and, through the use of closed-loop sensory stimulation, the patient is given continuous feedback for improving rehabilitation.
U.S. Pat. No. 6,360,597 to Hubbard, Jr., which is incorporated herein by reference, describes a gait analysis system that includes a shoe insert for use in a shoe worn by a subject while walking as part of a process of collecting gait data. The insert has force-sensing sensors distributed to define a sensing aperture, and each sensor provides an electrical output signal. Processing apparatus is communicatively coupled with the sensors. The processing apparatus calculates a gait line represented by a series of points, wherein each point is calculated as a spatially-weighted average of samples of the sensor output signals over the sensing aperture. The processing apparatus includes a portable telemetry transmitter worn by the subject. The transmitter is connected to the sensors to receive the sensor output signals, and transmits a radio signal carrying the sensor information. A stationary receiver receives the sensor information in a transmission from the transmitter, and provides the sensor information to a personal computer or similar workstation.
U.S. Pat. No. 6,611,789 to Darley, which is incorporated herein by reference, describes a method including determining, with at least one device supported by a user while the user is in locomotion on foot on a surface, an amount of force exerted by at least one foot of the user on the surface during at least one footstep taken by the user. In another embodiment, a method includes: (a) with at least one sensor supported by a user, monitoring movement of the user while the user is in locomotion on foot; and (b) determining a cadence of the user based upon an output of the at least one sensor. In another embodiment, a method includes: (a) with at least one sensor supported by a user while the user is in locomotion on foot, monitoring movement of the user while the user is in locomotion on foot; and (b) determining a stride length of the user during at least one footstep taken by the user based upon an output of the at least one sensor. In one embodiment, a display has simultaneously displayed thereon at least one determined performance parameter of the user (e.g., pace) and at least one determined variable physiological parameter of the user (e.g., heart rate).
U.S. Pat. No. 6,493,652 to Ohlenbusch et al., which is incorporated herein by reference, describes a method including, in response to movement of a user during at least one footstep taken by the user, generating a signal that experiences changes during a time period that the foot is airborne during the at least one footstep. At least one change in the signal generated after the foot has become airborne and before the foot contacts a surface is identified that is indicative of the foot being airborne during the at least one footstep. In another embodiment, a method includes generating a signal in response to movement of a user during at least one footstep taken by the user. The signal is monitored to determine when the signal has experienced a minimum degree of smoothness for at least a given period of time. In response to determining that the signal has experienced the minimum degree of smoothness for at least the given period of time, it is identified that the foot of the user is airborne.
U.S. Pat. No. 5,406,719 to Potter, which is incorporated herein by reference, describes a cushioning element for use in a shoe. The cushioning element includes four fluid-filled support chambers which are compressible but not collapsible, and which are disposed at different locations throughout the midsole of the shoe. The element also includes four variable volume fluid reservoir chambers which are collapsible to reduce the volume thereof. The reservoir chambers are controllably linked in fluid communication with the support chambers so as to be selectively in full communication with or isolated from the support chambers. By selectively isolating one or more of the reservoir chambers from one or more of the support chambers, and collapsing the isolated chamber, fluid may be moved from one support chamber to another at a different location, thereby increasing the stiffness of the midsole at a selected location.
U.S. Pat. No. 6,430,843 to Potter et al., which is incorporated herein by reference, describes an article of footwear with a dynamically-controlled cushioning system. The cushioning system includes a sealed, fluid-filled bladder formed with a plurality of separate cushioning chambers, and a control system. The control system, which includes pressure sensors and valves, controls fluid communication between the chambers to dynamically adjust the pressure in the cushioning chambers for various conditions such as the activity that the footwear is used in, the weight of the individual and the individual's running style. Certain adjustments can be made while the footwear is in use.
US Patent Application Publication 2003/0009913 to Potter et al., which is incorporated herein by reference, describes an article of footwear with a dynamically-controlled cushioning system. The cushioning system includes a sealed, fluid-filled bladder formed with a plurality of separate cushioning chambers, and a control system. The control system, which includes pressure sensors and valves, controls fluid communication between the chambers to dynamically adjust the pressure in the cushioning chambers for various conditions such as the activity that the footwear is used in, the weight of the individual and the individual's running style. Certain adjustments can be made while the footwear is in use.
U.S. Pat. No. 6,298,314 to Blackadar et al., which is incorporated herein by reference, describes methods for monitoring movement of a person, including using a sensor to generate a signal in response to movement of the person. In one embodiment, a characteristic in the signal is identified that indicates the person is walking or running and, in response to identifying the characteristic, a timer is started. In another embodiment, after the person has begun walking or running, a characteristic in the signal is identified that indicates the person has ceased walking or running and, in response to identifying the characteristic, an action is taken. In another embodiment, a characteristic in the signal is identified that is indicative of a foot of the person being in motion and, in response to identifying the characteristic, a timer is started. In another embodiment, after a foot of the person has been in motion, a characteristic in the signal is identified that is indicative of the foot ceasing to be in motion and, in response to identifying the characteristic, an action is taken. In another embodiment, in response to identifying that the person is not walking or running, a characteristic in the signal is identified that indicates the person has begun walking or running and, in response to identifying the characteristic, an action is taken. In another embodiment, in response to identifying that a foot of the person is stationary, a characteristic in the signal is identified that indicates the foot is in motion and, in response to identifying the characteristic, an action is taken.
U.S. Pat. No. 5,253,435 to Auger et al., which is incorporated herein by reference, describes a bladder assembly for an athletic shoe having at least first and second chambers. The chambers are independently and separately pressure adjustable by the user to conform to different concavity areas of his foot, such as the arch, ankle and metatarsal areas, to thereby enhance fit, comfort and athletic performance. Both chambers are inflatable by the same articulated on-board pump and deflatable by the same on-board depressible plunger. A dial on the lateral side of the upper allows the user to select which of the chambers is to be pressure adjusted, that is, which of the chambers is in pressure communication with the pump and the plunger. When the dial is in a neutral position, accidental inflation or deflation of either chamber is prevented.
U.S. Pat. No. 5,107,854 to Knotts et al., which is incorporated herein by reference, describes an orthopedic exercise chamber such as a slipper including a light-weight, self-contained limb load monitor is disclosed. The limb load sensor circuit provides extended service life for the miniature power supply that is included in the slipper, thereby making the slipper suitable for out-patient use. A fluid-filled plantar chamber that supports the entire load borne by the patient's foot is connected to the sensor circuit, thereby providing improved monitoring of the load being carried by the leg or foot that must be protected from excessive loading.
U.S. Pat. No. 6,646,643 to Templeman, which is incorporated herein by reference, describes techniques for interfacing locomotive 3D movements of a user to a reference in a virtual or remote environment are provided. Initially, a 3D motion of a body portion of a user is sensed as the user takes a gestural pace. This sensing includes the determining of a beginning and an end of the gestural pace taken by the user, the determining of a 3D direction characteristic of the body portion motion during the gestural pace, and the determining of a 3D extent characteristic of the body portion motion during the gestural pace. Next, a 3D direction and extent of motion in the environment corresponding to the determined direction and extent characteristics of the gestural pace is computed. Finally, the computed 3D motion is used to move the reference in the environment.
U.S. Pat. No. 6,539,336 to Vock et al., which is incorporated herein by reference, describes techniques for detecting the loft time, speed, power and/or drop distance of a vehicle, such as a sporting vehicle, during activities of moving and jumping. A loft sensor detects when the vehicle leaves the ground and when the vehicle returns to the ground. A controller subsystem converts the sensed information to determine a loft time. A display shows the recorded loft time to a user of the system. In addition, a speed sensor can detect the vehicle's speed for selective display to the user. A power sensing section informs the user of expended energy, which can be compared to other users. A drop distance sensing unit informs the user of the peak height of a jump, during an airtime. Gaming on the internet is facilitated to connect worldwide sport enthusiasts. The system can be integrated within a shoe and may thus be used by a jogger to evaluate different running shoes. Alternatively, when calibrated, the system is useful to joggers who can gate it to serve as a pedometer. The addition of a capacitor sensor in the heel helps determine average weight. A sensor for skin resistivity may additionally be used to record pulse. The shoe can also record the state of aerobic health for the jogger.
U.S. Pat. No. 6,398,740 to Lavery et al., which is incorporated herein by reference, describes techniques for monitoring items of vital health information including temperature of the plantar aspects of the foot of the human, body weight, blood pressure, pulse rate, blood glucose level and blood oxygen level. The apparatus includes a platform on which the user stands. Included on the platform are a set of heat sensitive signal generating devices. The temperature at predetermined locations on the plantar aspects of the human foot are determined by the signals obtained from the individual heat sensitive, signal generating probes. Other items of vital health information may be obtained by other sensors on the apparatus.
U.S. Pat. No. 5,642,096 to Leyerer et al., which is incorporated herein by reference, describes a shoe for prevention of ulcers in the feet of diabetes patients. The shoe includes a sensor disposed in a contained liquid mass of a hydrocell carried in the shoe inner sole, the sensor being one that detects both pressure and temperature values to which the patient's feet are exposed. The sensor includes a bridge circuit comprised of four piezoresistors arranged in two diagonally arrayed pairs, the resistance of one pair of resistors increasing and the resistance of the second pair decreasing in the presence of an increase in the pressure condition in the hydrocell, the resistance of all the resistors increasing or decreasing responsive to respective increases and decreases of temperature in the hydrocell. Outputs from the bridge circuit indicative of respective pressure and temperature values are acquired by a warning signal generator to operate same to generate a patient discernible warning signal that indicates to the patient a need to take action to avoid continuance of exposure to the condition. A grid array sensor detects localized pressure changes on the bottom of the foot by reducing the resistance between conductors present at the location of the increases pressure. The decreased resistance causes an increase in current flow between the conductors which is detected by a processor which in turn provides an indication of the increased pressure condition.
German Patent Application Publication DE 42 05 796 A1 to Thanscheidt, which is incorporated herein by reference, describes a base for shoes, especially sports shoes, that incorporates inflatable air chambers and an air pump with a valve housing. The housing is connected by a control to any one of the air chambers. The air pump has at least one supply cylinder containing a manually operated piston. The control is formed by an adjusting piston mounted in an adjusting cylinder parallel to the supply cylinder. The end of the adjusting piston has a cam for operating the valve(s) leading to an air chamber. Each valve has a spring loaded valve body guided by a guide pin in a connecting hole in the valve housing wall facing the adjusting cylinder.
The SmartStep® monitoring and biofeedback system (Andante Medical Devices Ltd., Be'er-Sheba, Israel) is a portable, miniature monitoring and biofeedback system for patients undergoing rehabilitation treatment.